LS4004 Human Physiology - Renal Physiology

Kidneys main 6 jobs

-blood composition regulation
-urine production/ waste removal
-production of hormones
-regulation of plamsa ph
-regulation of ions
-extracellular blood volume, blood pressure control

medulla of kidney

inner portion of kidney, composed of collecting tubules that empty into the renal pelvis

Uterer

Tubes tha carries urine from kidney to bladder

Urethra

Muscular tube that carries urine from the bladder to the outside of the body

Bladder

stores urine

High functional redundancy

A lot of the nephrons can fail before function is affected

Why is high functional redundancy bad?

Problems may not be detected until irreverable damahe has been done to the nephrons

kidney is concave or convex

concave

kidney is facing or away from spine

facing spine

normal osmolaroty

300osm

Thirst

Kidney controls thirst to keep blood around 290 Osm

Blood too acidic

Remove H+

Blood too alkaline

Remove HCO3 -

Why is the kidney so important?

Disturbances in blood volume or blood composition cause SERIOUS MEDICAL PROBLEMS!

An effect of low blood pressure

-no blood flow to organs

urinary system

kidneys, ureters, bladder, urethra

why are UTI chances higher for women?

The urethra is closer to the bladder in females, men have a penis between them, women only have a short distance

chain from blood to micturition

blood to nephron, becomes urine, to the ureter, to the bladder, to urethra, expulsion, process of micturition

medical term for unrination

micturition

what bacteria is most common in UTI cases

E.Coli is 80% of UTI cases

Renal arteries

give blood to kidney (Away from heart)

Renal Veins

feeds used deoxygenated blood into the inferior cava

Kidneys recieves ?% of cardiac output

20-25%

How does the blood move through the body via kidneys

The oxydenated blood in the body travels (from the aorta) around unfiltered just giving out oxyen and travelling back to the heart.

The unflitered oxgenated blood travels from the aorta to the renak atery, which goes tpo the kidney, which used the oxygen and filters to blood, the feeds the deoxygenated blood and flows out urine.

afferent arterioles

renal artery spilts and spilts until the afferent arterioles which - carry blood unto the glomerulus (that blood gives the oxydgen needed for filtration)

efferent arterioles

small artery that carry blood away from the glomerulus after filtation has occured, this splits into the peritubular carpillaries

Bowman's capsule

cup-shaped strucutre of the nephron of a kidney which encloses the glomerulus and which filtration takes place.

peritubular capillaries

The network of tiny blood vessels that surrounds the proximal and distal tubules in the kidney

Promixal convoluted tubule

Tubule that comes from the glomerulus, before the loop of Henle

Responsible for isosmotic reabsorption of water and nutrients

distal convoluted tubule

Between the loop of Henle and the collecting duct; Selective reabsorption and secretion occur here, most notably to regulate reabsorption of water and sodium

Loop of Henle

section of the nephron tubule that is responsible for conserving water and minimizing the volume of the filtrate

juxtamedullary nephrons

Nephrons that dip into the medula. they have longer loops of henle

cortex of kidney

outer layer of kidney that contains nephrons

Vasa recta

peritubular capillaries that serve juxtamedullary nephrons

peritubular capillaries merge into

venules, to veins, to the renal vein

tubules of the kidney

passageways, epithelial cells, tight junctions, selective permulability for ions

Bowman's Capsule

a hollow, ball shaped structure,

consuists of 2 layers
1) podocytes - footlike cells that wrap around the glomular carpillaries, cutting small gaps in the them, allowing the passage of filtrate

2) Parietal Layer- simple sqaumous layer of epilial cells that provide structural support

glomerulus

The ball of capillaries at the beginning of the nephron where blood filtration takes place.

what % of the nephrons dip into the medula?

Only 20%

Juxtaglomerular apparatus

The aff-erent arteriole and loop of Henle

The Afferent artoerole does parachute sinalling (letting out hormones that act of nearby cells) with the distal convuled tubule to:
Control salt levels
Regulate blood flow
water reabsorption

Where is the ascending limb of the loop of henle?

The loop of Henle loops back on itself so that acending limb is between the afferent and efferent arterioles

what ans where is reabsorbtion

movement of sunstances from the kidney tubule to blood vessels

pertibular carpillaires

what is secretion

movement og molecules from blood vessels back into the kidney tubules

why does secretion occur?

some molecules were too big to enter tubule at glomerulus

Total pressure in nepron

10mmHg

Carpillary ONCOTIC [colloid] Pressure

Pulling force from proteins in water/blood plasma, keeping water in the capillaries [prevents leaking]

-30mmHg

Carpillary pressure

Blood prshing against the walls of the [any] capillary in the body

affected by the body

the capillary pressure provides the concentration gradient for diffusion to occur for the exchange of substances

Glomeular Hydrostatic pressure

Capillary pressure localised to the glomelular carpillairies

Driving force for filtration, drives substajnces out ofthe carpillaries [FILTRATION]

controlled by kidney

glomerular filtration rate

volume of fluid filtered from the glomeruli of the kidneys into the renal tubules per unit of time

Countercurrent multipication mechanism

DESCENDING LIMB:
water leaves PASSIVELY to help equilibriate molarity with interstitial fluid

ACENDING LIMB:
sodium pumped out to decrease molarity. Has to have 200OsM diffrernce with interstitial fluid.

COUNTERCURRENT MULTIPLICATION
NAME ORIGIN

COUNTERCURRENT: descending, then ascending

MULTIPLICATION:
molarity increases [multiplies] as you go further

RAAS

renin-angiotensin-aldosterone system

Angiotensin --Renin--> Angiotensin I --ACE--> Angiotensin II -------> Aldosterone

renin

Realeased by the blood when Kidney detects low blood Pressure or low sodium levels

aldosterone

HORMONE

works in kidney
increases sodium reabsorption to increase blood sodium
increased water reabsorption to increase blood volume- blood presure

angiotensin

Angiotensin - found in lungs

Angiotensin I - substrate for ACE [angiotenin converting molecule{found in the lungs}]

Angiotensin II - POTENT vasoCONSTRICTOR [increases blood pressure even before aldosterone]

ADH

antidiuretic hormone

diuresis

increased formation and secretion of urine

Naturesis

increased urinary excretion of Na

Diruetics

Drugs that promotes diuresis (above phsiologic levels)

Direct and Indirect effects of diuretics

DIRECT:
works on nephrons
affects ion pumps, receptors, enzymes

INDIRECT:
increased plasma volume
increased kidney blood flow
increased water retention

NEED TO REDO

COUNERCURRENT MULTIPLICATION
PULLING FORCES AND PRESSURE
PORTAL SYSTEM
THIRST

osmoticc diuretics

PROMOTOE DIURESIS BY CREATING A AN OSMOTIC GRADIENT IN THE KINDEY TUBULES

Symptoms of UTI

Pain from urination, increased urination

Glomerulus function

filtration of blood

What and where is filtatrion

movemnet of substances from blood vessel to tubule

only in bowmans capsule